Modular compressor-valve design for refrigerant system

ABSTRACT

A compressor-valve modular design provides manufacturing simplicity, reduces applied cost, and improves quality and reliability of a refrigerant system. In this design, a valve is preferably an electronically controlled valve having a control member that controls the flow of a fluid through the valve. A discharge valve, a stepper motor modulation valve, an economizer vapor injection valve, a liquid injection valve or any combination of thereof are the examples of the valves within the compressor-valve subassembly.

BACKGROUND OF THE INVENTION

This application relates to a method and system wherein acompressor-valve modular design is implemented to provide manufacturingsimplicity, reduce applied cost and improve quality and reliability. Inparticular, this application relates to a refrigerant system whereinperformance enhancement features are implemented and associated with(and adjacent to) at least one of the compressor ports.

Refrigerant systems are known and utilized to condition a secondaryfluid to provide comfort in an indoor environment. As an example, an airconditioning system cools and dehumidifies air being delivered into anindoor environment.

Conventional refrigerant systems generally include a compressorcompressing refrigerant and delivering that refrigerant through adischarge line to a downstream heat exchanger, so-called a condenser.From this first downstream heat exchanger, refrigerant passes through anexpansion device and then through a second heat exchanger, so-called anevaporator. The refrigerant is then returned to the compressor.

Beyond this very basic refrigerant system description, any number ofoptional features can be incorporated to either improve systemperformance and reliability or extend a spectrum of potentialapplications. As an example, to provide certain control features, suchas a prevention of undesirable backflow of refrigerant from a highpressure location to a lower pressure location within the refrigerantsystem after compressor shutdown, a controlled discharge valve can beplaced on a discharge line. Similarly, a modulation valve can be placedon a suction line communicating the second heat exchanger back to thecompressor for the refrigerant system capacity control.

Another optional feature is an economizer vapor injection cycle. In aneconomizer cycle, a flow of refrigerant is tapped off from a main flowdownstream of the first heat exchanger. The tapped flow is passedthrough an auxiliary expansion device that causes the refrigerant toexpand to a lower pressure and temperature. This tapped refrigerant isthen passed through an economizer heat exchanger for heat transferinteraction with the main refrigerant flow. The tapped refrigerant flowcools the main flow. The tapped flow is typically returned through aneconomizer line to the compressor at an intermediate compression point.Again, a vapor injection valve controls the flow of this refrigerantbeing returned to the compressor. Analogously, a liquid injectionfeature can be employed, where a liquid is injected either intocompressor suction or into intermediate compression stage. To controlthe liquid injection, a valve is normally employed to turn the liquidinjection function on and off.

In the prior art, each of these several valves associated with thecompressor has been independently produced and implemented within therefrigerant system. The independent implementation of these valves intothe system often required additional assembly during systemmanufacturing and could be a source for mistakes and unnecessarycomplexity.

SUMMARY OF THE INVENTION

In a disclosed embodiment of this invention, a compressor-valve modularsubassembly is implemented to provide manufacturing simplicity, reduceapplied cost and improve quality and reliability for a refrigerantsystem where performance enhancement features are desired and associatedwith at least one valve adjacent to at least one compressor port. Withinthis subassembly design, a valve is preferably an electronicallycontrolled valve having a control member that controls the flow of afluid from the valve inlet line to the valve outlet line. As an example,the valve can be utilized as a discharge valve, a suction modulationvalve, an economizer vapor injection valve, a liquid injection valve orany combination of thereof. Valves can be solenoid valves ormotor-driven modulation valves. Further, a function of two valves can becombined into a three-way valve. The valves are located outside of thecompressor shell. The compressor shell normally surrounds the internalcompression elements within the compressor. The compressor shell can bea so-called welded compressor shell or a cast iron compressor shell,which is typical, for instance, for screw or reciprocating compressors.

In this manner, a relatively inexpensive compressor-valve subassembly isproduced, manufacturing complexity is reduced, enhancement features areimplemented and refrigerant system quality and reliability are improved.

These and other features of the present invention can be best understoodfrom the following specification and drawings, the following of which isa brief description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a refrigerant system.

FIG. 2 shows a first location of the valve within a compressor-valvemodular subassembly.

FIG. 3 shows another location of the valve within a compressor-valvemodular subassembly.

FIG. 4 shows yet another location of the valve within a compressor-valvemodular subassembly.

FIG. 5 schematically shows a method according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A refrigerant system 18 illustrated in FIG. 1 incorporates a compressor20. The compressor 20 delivers a compressed refrigerant to a downstreamdischarge valve 22, and through a discharge line 24. Discharge valve 22is typically used to prevent a backflow of refrigerant during shutdownsof the compressor 20, or can be utilized as a discharge pressureregulator. This valve can be electronically controlled. Refrigerantflowing from the discharge line 24 through the valve 22 passes into adownstream line 26 that delivers the refrigerant flow to a condenser 28.When the compressor is shutdown, the valve 22 blocks the refrigerantfrom passing from the condenser 28 into the compressor 20 and then intoan evaporator 58. A tap line 30 taps refrigerant from a liquid line 32downstream of the condenser 28. The tap line 30 passes through aneconomizer auxiliary expansion device 31. The tapped refrigerant in thetap line 30 and the liquid refrigerant in the liquid line 32 both passthrough an economizer heat exchanger 34. While the two refrigerantstreams are shown flowing in the same direction, in practice, it isoften preferable to have the two flows arranged in a counterflowconfiguration. The tapped refrigerant in the tap line 30, having cooledthe refrigerant in the liquid line 32 in the economizer heat exchanger34, is directed to a line 36 toward the compressor 20. A vapor injectionvalve 38 can shut off the flow of this returned vapor refrigerant. Thevapor injection valve 38 is connected to a downstream return line 40.Analogously, a liquid injection valve can be employed, in case aneconomizer heat exchanger is not present or is bypassed. Liquidinjection is typically used to cool the compressor and may or may notshare the same port with the vapor injection function. Refrigerantpassing through the dedicated liquid injection line can be injectedeither into the compressor suction or directly into the compressionprocess, as known.

The suction line 52 can have an optional motor driven modulation valve(suction modulation valve) 54. The main refrigerant flow, having passedthrough the economizer heat exchanger 34, passes into a line 55, througha main expansion device 56, to the evaporator 58, and through thesuction modulation valve 54 to a suction line 52. Suction modulationvalves are usually used to provide capacity control for the refrigerantsystem 18. The suction modulation valve 52 can also be used inrefrigerant systems that are not equipped with economized cycles.

Each of the valves 22, 38, and 54 can be controlled by an electroniccontrol for the refrigerant system 18 and could be of an identicaldesign. Any of these valves can, for example, be a solenoid valve orMotor driven modulation valves.

FIG. 2 shows a modular compressor-valve subassembly with a compressor198 having its discharge line 200 receiving the discharge valve 100. Thedischarge valve 100 is typically utilized to block the refrigerantbackflow during the compressor shutdowns, or is utilized as a dischargepressure regulator.

FIG. 3 shows a modular compressor-valve subassembly with the compressor198 having a suction line 202 receiving a suction modulation valve 101.The suction modulation valve 101 is generally used to control systemcapacity.

FIG. 4 shows a modular compressor-valve subassembly with the compressor198 having a vapor or liquid injection line 204 receiving a vapor orliquid injection valve 102. The valve 102 is commonly employed to injectliquid (to cool the compressor) or vapor (for an economizer cycle) intointermediate point in the compression process. As mentioned above,liquid injection and vapor injection ports do not necessarily coincide.

It should also be pointed that other valve arrangements are possiblewhere, for example, a valve may provide a fluid connection between thefluid lines attached to the compressor. In this case the valve canselectively isolate higher pressure compressor port from lower pressurecompressor port.

Although preferred locations for the use of the valves are disclosed,other arrangements or a combination of the abovementioned arrangementsmay also be utilized. A compressor-valve design as a modularsubassembly, where the associated valves are an integral part of thecompressor, provides manufacturing simplicity, reduces applied cost andimproves quality and reliability for a refrigerant system whereperformance enhancement features are desired and associated with atleast one valve adjacent to at least one compressor port.

In contemporary applications, since refrigerant systems operate at awide spectrum of environmental conditions, exposed to a variety ofthermal load requirements and, as a result, have multiple enhancementfeatures; many valves are implemented to invoke this functionality andare associated with the compressor. Consequently, it is beneficial forthe manufacturing simplicity to preassemble a module consisting of acompressor and associated valves. In this case, this module will havestrictly defined interfaces to other system components and allow for amore compact design and reduced cost, due to a modular design concept.Also, utilizing preassembled module, the chance of a defect is reducedor would surface early enough in the manufacturing process, consequentlyimproving quality and reliability.

As shown in FIG. 5, a modular compressor 20 and valving systemsubassembly 300 can include any one or all of the valves 100, 101, 102,and as mentioned, other valves, as a modular subassembly. This modularsubassembly 300 can be manufactured at a compressor assembly plant,where more skilled technical assembly workers are available. Thatmodular compressor and valving system subassembly 300 can then beshipped to a location where the refrigerant system 18 is to beassembled. As mentioned above, by providing the modular subassembly,benefits with regard to simplicity of a final assembly are achieved.

Within this subassembly design a valve is preferably an electronicallycontrolled valve having a control member that controls the flow of afluid from the valve inlet line to the valve outlet line. The inlet andoutlet lines to the valve can be provided with inserts or adapters suchthat, if the same valve is utilized, it can be connected to refrigerantlines of various sizes. Further, by utilizing a common modular valve,the cost for designing, manufacturing, implementation, etc., of thevalves is reduced even further, as compared to the prior art. This makesthe use of the several optional refrigerant system enhancementfunctions, as disclosed in this application, to become more practicaland affordable. It should be noted that this invention is applicable tomany different compressor types, for example, including scrollcompressors, reciprocating compressors, screw compressors, rotarycompressors, and reciprocating compressors. Other compressor types wouldobviously fall within the scope of this invention as long as there is acompressor and a valve comprising an integral module. This invention isalso applicable to a broad range of applications, for example, includingcontainer and truck-trailer refrigeration units, room and residentialair conditioning units, commercial refrigeration and air conditioningsystems, automotive air conditioning, and rooftop installations andchillers.

Although a preferred embodiment of this invention has been disclosed, aworker of ordinary skill in this art would recognize that certainmodifications would come within the scope of this invention. For thatreason, the following claims should be studied to determine the truescope and content of this invention.

1. A refrigerant apparatus, comprising: a compressor having a compressorshell and at least two compressor ports; and at least one valve, fluidlyconnected to said at least one compressor port outside of saidcompressor shell to enhance compressor functionality within arefrigerant system, wherein said valve and said compressor comprising anintegral module.
 2. The refrigerant apparatus as set forth in claim 1,wherein said at least one valve is fluidly connected to a discharge portof said compressor.
 3. The refrigerant apparatus as set forth in claim1, wherein said at least one valve is fluidly connected to a suctionport of said compressor.
 4. The refrigerant apparatus as set forth inclaim 1, wherein said at least one valve is fluidly connected to aliquid injection line of said compressor.
 5. The refrigerant apparatusas set forth in claim 1, wherein said at least one valve is fluidlyconnected to a vapor injection port of said compressor.
 6. Therefrigerant apparatus as set forth in claim 1, wherein said at least onevalve is an electrically controlled valve.
 7. The refrigerant apparatusas set forth in claim 6, wherein said electrically controlled valve is asolenoid valve.
 8. The refrigerant apparatus as set forth in claim 6,wherein said electrically controlled valve is a stepper motor modulationvalve.
 9. A method of assembling a refrigerant system comprising thesteps of: 1) providing a modular subassembly of a compressor and anassociated at least one valve mounted outwardly of a shell for saidcompressor, said modular subassembly being manufactured at a firstlocation; and 2) transporting said modular subassembly to a finalassembly location where a refrigerant system is being assembled, andconnecting said modular subassembly to a refrigerant system.
 10. Themethod as set forth in claim 9, wherein said at least one valve isfluidly connected to a discharge port in said compressor.
 11. The methodas set forth in claim 9, wherein said at least valve is fluidlyconnected to a suction port in said compressor.
 12. The method as setforth in claim 9, wherein said at least one valve is fluidly connectedto a liquid injection line in said compressor.
 13. The method as setforth in claim 9, wherein said at least one valve is fluidly connectedto a vapor injection line in said compressor.
 14. The method as setforth in claim 9, wherein said at least one valve is an electricallycontrolled valve.
 15. The method as set forth in claim 14, wherein saidelectrically controlled valve is a solenoid valve.
 16. The method as setforth in claim 14, wherein said electrically controlled valve is astepper motor modulation valve.